Rotary hammer



April 10, 1934. 1 s, c, JENSEN 1,954,175

ROTARY HAMMER I Original Filed July 28, 1931 2 Sheets-Sheet, l

III

gwuentoc April 10, 1934. s. c. JENSEN 1,954,175

ROTARY HAMMER Original Filed July 28, 1931 2 Sheets-Sheet 2 gwuantocPatented Apr. 10, 1934 PATENT OFFICE ROTARY HAMMER Sanning C. Jensen,Neola, Iowa.

"Application July 28, 1931, Serial No. 553,627 Renewed September 12,1933 6 Claims.

This invention relates to improvements in hammers for hammer mills.

In hammer mills employing the swing type hammer a series of pivotallymounted hammers are rotated at high speed over a screen through whichthe grain, or other matter which is ground by the revolvinghammerspasses. These hammers, when new, have sharp edges which cut thegrain against the screen but these edges rapidly wear away until theybecome rounded'and when this condition is reached the hammer has to beturned for the presentation of another one of its four cutting edges.Due to the high speed at which the machines are operated, each hammerhas to be completely replaced after a few months use.

The primary object of the present invention is to provide an improvedtype of hammer which is so designed that a sharp cutting edge ismaintained even though the edge of the hammer which is presented to thescreen becomes rounded off through use and therefore the life of ahammer constructed in accordance with the present invention is muchgreater than one of the type at present employed.

A further object of the invention is to provide a hammer which, inaddition to being so designed as to continuously present a sharp edgefor the cutting of grain, is so formed as to cause the grain, or othermaterial upon which it is working, to be forced or thrown into the pathof the cutting edge. 7

The invention will be best understood from a consideration of thefollowing detailed description taken in connection with the accompanyingdrawings forming part of this specification, with the understanding,however, that the invention is not confined to any strict conformitywith the shgwing of the drawings but may be changed or modified so longas such changes or modifications mark no material departure from thesalient features of the invention as expressed in the appended claims.

In the drawings:

Figure 1 is a perspective view of a rotary hammer constructed inaccordance with the present invention.

Figure 1a is a sectional view taken in a plane parallel with the sidefaces of the hammer shown in Figure 1, at one end, showing the manner inwhich the end of the hammer wears away.

Figure lb is a fragmentary view in elevation of the inner structure of ahammer mill showing the hammers applied thereto.

the form shown in Figure 5, showing the manner in which the hammerwears.

Figure 6-is a perspective view of one end of a fifth modified form.

Figure 7 is a perspective view of one end of a sixth modified form.

Referring now more particularly to the drawings, wherein like numeralsof reference indicate corresponding parts throughout the several views,the numeral 1 indicates a portion of a mill of the type in whichswinging hammers of the character embodying the present invention areemployed. These mills have a plurality of plates or disks 2 which areconcentrically mounted in spaced relation upon a carrying shaft 3 andare connected at points about and adjacent their peripheries by bars orrods 4. Upon these bars are mounted, adjacent their ends, the hammers 5which, when the plates are rotated, are caused to stand out throughcentrifugal force away from the bars upon which they are mounted. Thehammers 5 illustrate one of the several modified forms of hammerembodying the present invention, one of which is shown in perspective inFigure 1. This form of hammer, which is indicated by the numeral 5,comprises an elongated relatively thick plate of highly tempered steelthrough which is formed, adjacent each end, an opening 6 for the passageof a rod 4. At each end of the hammer body, each corner is cut away toform the series of step-like shoulders 7, the corners 8 between whichconstitute the cutting edges. v

These edges wear away after the hammer has been in usefor a short periodof time and become rounded, as indicated at 9 in Figure 1a. It will bereadily seen from this that this rounded edge could no longer functionas a cutting element and therefore the hammer would no longer be of use.

In carrying out the present invention each end of the hammer body isprovided with a bore 10 which is cut therethrough from one face of oneof the step-like shoulders to the opposite one and as a result it willbe seen upon reference to Figure la that, although the previously sharpcorner 8 wears away to the rounded condition indicated by the numeral 9,a sharp cutting edge remains at the point 11 which extends throughoutsubstantially half the circumference of the bore. It will thus be seenthat while the wearing down of the corner 8 takes away the originalsharp cutting edge another cutting edge is formed where the worn surfaceextends across the bore 10, which continues to function as a cutter forthe grain or other material against which the hammer strikes.

In Figure 2 there is shown a modified form of the hammer illustrated inFigure 1, wherein each end of the body 12 is provided with a straightterminal portion 13 across each side face of which so i is formed aV-shaped groove 14 and this portion of the body has formed therethroughfrom one edge face tothe other, between the grooves 14, a passage 15.

In Figure 3 the straight terminal portion of the hammer body 16 has itstransverse corners beveled off to form an end which is in the form of aninverted V, as indicated by the numeral 17, and from one edge face tothe opposite edge face between the beveled sides of this inverted V-shaped end there is formed through the body the passage 18.

In Figure 4 the body 19 has each end edge formed with a pair oflongitudinally extending V-shaped ribs 20-, and extending through eachend, from one side edge to the other, are the two passages or bores 21each of which is parallel with and disposed between the angled faces ofa rib in the manner illustrated.

In Figure 5 the hammer body 22, which is shown, has two straightterminal end portions 23 the same as in the other forms and the end edgeof each of these portions is left flat, as in the form shown in Figure1, but instead of a single bore extending through each of these endportions from one side edge to the other there are formed two bores,each of which is indicated by the numeral 24, which are disposed in sideby side relation.

The form of hammer shown in Figure 6 is substantially the same as thatshown in Figure 5, except that each straight end portion 25 of the body26 has in place of a pair of circular bores of the character indicatedby the numeral 24, one or more passages 2'7 of triangular crosssection,one side of the angle being in relatively close proximity to andparallel with the face of the adjacent end edge.

Figure 7 illustrates still another form of hammer wherein the body 28has the straight end portions 29 of the same character as the portions23 and 25, but in place of the passages of the character shown inconnection with the forms illustrated in Figures 5 and 6, one or moresquare passages 30 is formed from one side edge to the other of each endportion, it being preferred that three small passages of this characterbe em,- ployed and disposed in side by side relation in the mannershown, each having a side parallel with the adjacent end edge face.

Figure 5a illustrates the manner in which a pair of curved cutting edgeswould be formed through the wearing away of a corner of the straightportion of a hammer of the character illustrated in Figure 5. It will beseen that through the wearing away of the corner of the straight endportion 23 of this hammer two curved cutting edges 31 are formed by thebores being cut obliquely through the wearing away of the body. It willthus be seen that whereas a hammer of this character would becomeuseless after being worn in the manner illustrated. if these bores werenot provided, by the provision of these bores two extra cutting edgesare formed which makes it possible to continue the use of the hammerover a long period of time.

In addition to forming each end of the hammer in one of the severalmodified forms illustrated for the purpose of providing an additionalcutting edge in the manner described, the mill in which the hammer isused is made more efficient by forming each hammer of a much greaterwidth between its side edges and substantially midway between its endsso as to provide each side edge' with the two inclined shoulders 32which taper inwardly in the manner illustrated.

The hammer bodies thus gradually decrease in width from their transversecenters toward the straight end portions thereof and in this manner thegrain, or other material, is driven toward the free ends of the hammersas they rotate in the mill.

From the foregoing description it be readily seen that by the use ofhammers of the character herein described the operation of the mill willbe made much more economical, due to the fact that the hammers will nothave to be replaced as is necessary at the present time.

Having thus described the invention, what is claimed is:

1. A rotary hammer, comprising an elongated flat plate-like body havingan aperture through one end and having the end and side edges remotefrom the apertured end formed to provide cutting corners, and the saidlast mentioned and having a passage formed therethrough from one sideedge to the other and parallel with the side faces of the body.

2. A rotary hammer, comprising an elongated flat plate-like body havingan aperture transversely through one end and having the end remote fromsaid aperture cut square across to form cutting corners, said lastmentioned end of the body having a passage formed therethrough parallelto the side faces of the body and from one side edge to the other and inrelatively close proximity to the square cut end edge.

3. A rotary hammer, comprising an elongated flat body tapering at itsside edges from the transverse center thereof toward each end andterminating at each end in a straight portion faces and end edge facesat right angles thereto,-

said straight portions having grooves formed transversely of the sidefaces thereof and further having a passage formed therethrough parallelwith the end edge faces and opening through the side edge faces thereof,the body further having an aperture opening through the side faces ateach end.

5. A rotary hammer, comprising an elongated fiat body having straightend portions, each end portion having the side comers beveled off toform a central edge extending from one side edge to the other, and eachend portion further havside edge faces, the end portions being formed toprovide a ridge having an edge extending from one side edge face to theother, and the end portions further having a. passage formedtherethrough from one side edge face to the other and paralleling theside faces thereof SANNING C. JENSEN.

